Method for manufacturing electrically conductive macromolecules and solid state electrolytic capacitor using electrically conductive macromolecules

ABSTRACT

The method for manufacturing electrically conductive macromolecules of the present invention is provided by reacting at least a monomer and an oxidizing agent to obtain electrically conductive macromolecules by a chemical polymerization method, the method including reacting the monomer and the oxidizing agent at least in a polymerizing vessel that contains a steam atmosphere. With this method, it is possible to obtain flat, electrically conductive macromolecules ( 10 ). Thus, it is possible to provide a method and an apparatus for manufacturing electrically conductive macromolecules in which it is possible to combine both low ESR and high capacity in a solid state electrolytic capacitor, realize low losses, and have low current leakage.

TECHNICAL FIELD

The present invention relates to methods and apparatuses formanufacturing electrically conductive macromolecules that are useful inelectronic components and solid state electrolytic capacitors, forexample.

BACKGROUND ART

Electronic components, in particular solid state electrolytic capacitorsin which electrically conductive macromolecules are used, are describedas one example of the conventional art. In recent years, there has beena noticeable increase in the frequency and the current of integratedcircuits of electronic devices in which solid state electrolyticcapacitors are used. Accordingly, there is a demand for solid stateelectrolytic capacitors whose equivalent series resistance (abbreviatedas “ESR”) is low, that have a large capacity and that have small losses.The conventional method for manufacturing an internal electrode (that isto say, a capacitor element) of a solid state electrolytic capacitor isillustrated for solid state electrolytic capacitors. First of all, valvemetal (for example tantalum metal) that is to be the anodic conductor isanodized in an electrolytic solution such as phosphoric acid to form anoxide film layer (dielectric layer) on the surface. Next, a solid stateelectrolyte is formed on the surface of the oxide film layer. Manganesedioxide, which can be formed by, for example, immersing the anodicconductor in a manganese nitrate solution, withdrawing, and then firing,is known as a solid state electrolyte. Finally, a cathodic conductor isformed on the solid state electrolyte. A laminated body of, for example,a carbon layer and a silver-surface conductive resin layer can be usedfor the cathodic conductor. In order for the capacitor element toconnect electrically with the exterior, an anodic lead terminal and acathodic lead terminal respectively are connected to the anodicconductor and the cathodic conductor.

Although the above-noted members individually may influence the ESR bytheir own resistance, the solid state electrolyte is the material thatshould be given the most consideration with respect to resistance. Inorder to reduce the resistance of the solid state electrolyte, it hasbeen proposed that an electrically conductive macromolecular materialwhose conductivity is higher than that of manganese dioxide (which has aconductivity of about 0.1 S/cm), and this has come into regular use. Forexample, if polypyrrole is used, then it is possible to realize aconductivity of about 100 S/cm. In addition to pyrrole, compounds suchas aniline, thiophene and 3,4-ethylenedioxythiophene are known asmonomers for constituting electrically conductive macromolecularmaterial. Methods for forming electrically conductive macromolecularlayers are divided broadly into chemical oxidation polymerization andelectrolytic oxidation polymerization.

Contact resistance between layers also affects ESR. In Patent Reference1, below, which is by the applicant of the present application, it hasbeen disclosed that by mixing electrically conductive polymermicro-particles into the electrically conductive macromolecular layer,contact resistance between the electrically conductive macromolecularlayer and the cathodic conductor is reduced by the surface roughnessthat is formed by the micro-particles. In the method described in thispublication, the electrically conductive macromolecular layer is formedby a chemical oxidation polymerization method in which a polymerizationsolution that is a dispersion of the electrically conductive polymermicro-particles is used.

In order to greatly increase the capacitance of capacitors, it also hasbeen proposed to form the electrically conductive macromolecular layerin particle form. In Patent Reference 2 below, it has been disclosedthat particulate polypyrrole having a particle diameter of 0.2 μm orless is formed by chemical oxidation using a polymerization solution inwhich the molar ratio of the mixture of oxidizing agent to monomer is atleast 1. If the particle diameter of the electrically conductivemacromolecular layer is reduced, then delamination of the layer can besuppressed and it is easier to gain use of dormant capacitance containedwithin the dielectric layer.

In Patent Reference 3 below, a method for manufacturing a solid stateelectrolytic capacitor is disclosed, the method including a process forforming an electrically conductive polymer layer on a synthetic film byimmersing a capacitor element in a solution that includes a monomer,which becomes the electrically conductive polymer by oxidationpolymerization, and an oxidizing agent, after which the capacitorelement is left to stand in air at a temperature of about 30° C. to 50°C. and a relative humidity of at least about 60%. This is with theobject of clarifying preferable conditions for forming an electricallyconductive polymer layer by chemical polymerization on a capacitorelement that includes an anodic member on which a synthetic film isformed, and providing a solid state electrolytic capacitor that iscompact, that has a large capacity, that has a low ESR and that hassuperior productivity.

Patent Reference 1: JP 2000-232036A

Patent Reference 2: JP H8-45790A

Patent Reference 3: JP H10-64761A

As given above, numerous investigations have been carried out withregard to solid state electrolytic capacitors in which electricallyconductive macromolecular layers are used as solid state electrolytes.However, compatibility between low ESR and high capacity in solid stateelectrolytic capacitors, and also realization of low losses andreduction of leakage current have not yet been sufficiently achieved.

DISCLOSURE OF INVENTION

In order to solve the above problem, the present invention provides amethod and an apparatus for manufacturing electrically conductivemacromolecules in which it is possible to combine both low ESR and highcapacitance in the solid state electrolytic capacitor, and also realizelow losses and low current leakage, and to provide a method formanufacturing electronic components and solid state electrolyticcapacitors in which the electrically conductive macromolecules are used.

The method for manufacturing electrically conductive macromolecules ofthe present invention is a method for manufacturing electricallyconductive macromolecules by reacting at least a monomer and anoxidizing agent to obtain electrically conductive macromolecules by achemical polymerization method, the method comprising; reacting themonomer and the oxidizing agent in a polymerizing vessel that containsat least a steam (water vapor) atmosphere.

The apparatus for manufacturing the electrically conductive molecules ofthe present invention is an apparatus for manufacturing electricallyconductive macromolecules, for polymerizing at least a monomer and anoxidizing agent in a polymerizing vessel, wherein the polymerizingvessel that contains steam atmosphere includes a device for providingdry air and steam that is generated by a heat exchanger to thepolymerizing vessel, at least in the polymerizing vessel, and whereinthe reaction of the monomer and the oxidizing agent at least occurswithin the polymerizing vessel in the steam atmosphere.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A is a cross-sectional view showing an example of an electricallyconductive macromolecular film that is formed on a glass substrate inWorking Example 1 of the present invention and FIG. 1B is across-sectional view showing an electrically conductive macromolecularfilm of a comparative example.

FIG. 2A is an example of a photo taken by an optical microscope, of theelectrically conductive macromolecular film formed on the glasssubstrate in Working Example 1 of the present invention, and FIG. 2B isa photo taken by an optical microscope of the electrically conductivemacromolecular film of the comparative example.

FIG. 3 is a view showing an example of a cross-section of anelectrolytic capacitor according to the present invention.

FIG. 4 is a view showing an example of the arrangement of polymerizingelectrodes used in performing the method of the present invention.

FIG. 5A is a plan view for explaining how the polymerized film that ispolymerized in a dry atmosphere of the comparative example is attached,FIG. 5B is a cross-sectional view of the same, and FIG. 5C is anexplanatory diagram for showing a ratio d/L of a separation distance dfrom the cross-section of the anodic conductor of the first electricallyconductive macromolecular layer, to a length L in the direction of thecross-section of the anodic conductor.

FIG. 6A is a plan view for explaining how the polymerized film that ispolymerized in a steam atmosphere of Working Example 2 is attached, andFIG. 6B is a cross-sectional view of the same.

FIG. 7A is a graph showing the relationship of electrostatic capacitanceat a frequency of 120 Hz, and the steam concentration and polymerizationtemperature in Working Example 2 of the present invention, and FIG. 7Bis a graph showing the relationship of electrostatic capacitance at afrequency of 100 kHz, and the steam concentration and polymerizationtemperature in Working Example 2 of the present invention.

FIG. 8A is a graph of the ESR of Working Example 2 of the presentinvention when measured at a frequency of 100 kHz, and FIG. 8B is agraph of the leakage current 30 s after applying a voltage of 2.5 V tothe solid state electrolytic capacitors of Working Example 2.

FIG. 9 is a diagram that schematically shows an example of an apparatusfor manufacturing the electrically conductive macromolecules used inperforming the method of the present invention.

FIG. 10 is a diagram that schematically shows an example of an apparatusfor manufacturing the electrically conductive macromolecules used inperforming the method of the present invention.

BEST MODE CARRYING OUT THE INVENTION

The present invention includes reacting at least a monomer and anoxidizing agent to obtain electrically conductive macromolecules by achemical polymerization method, wherein the monomer and the oxidizingagent are reacted at least in a polymerizing vessel that contains asteam atmosphere. Furthermore, it is desirable that the steamconcentration of the steam atmosphere is at least 5 vol %. This is inorder both to reduce the vaporization speed of the solvent, and toincrease the temperature of the polymerized body. If the steamconcentration is less than 5 vol %, then it tends to be difficult toachieve both.

It is desirable that the temperature of the steam atmosphere is at least85° C. The polymerization reaction rate increases with increasedtemperature, and thus it is possible to increase the yield of thepolymer film, and decrease the time for the polymerization reaction.

Before reacting the monomer and the oxidizing agent in a polymerizingtank having a steam atmosphere, it is possible that preliminarypolymerization is performed in advance at a temperature of less than 85°C. By preliminary polymerization, the polymerization solution seeps intofine aperture portions by capillary action, and reacts, and there is anadvantage in that it is possible to fill the polymer film into theinternal portions of the fine apertures.

Furthermore, it is desirable that the concentration of oxygen in thesteam atmosphere is less than 21 vol %. In this way, it is possible toprevent oxidation degeneration of the previously formed polymer filmwhen repeating the polymerization.

Furthermore, it is desirable that the monomer is at least one ofpyrrole, thiophene, 3,4-ethylenedioxythiophene and aniline, and theirderivatives, and that that the oxidizing agent is at least one ofmanganese oxide, iron (III) salts, copper (II) salts, hydrogen peroxideand persulfate salts, and that the monomer and the oxidizing agent areat least dissolved in a water soluble solvent or water. Thus, there isan increased affinity when the steam adheres to the polymerized body,and it is easier to obtain a polymer body that is film-shaped.

Furthermore, it is preferable that when observing the electricallyconductive macromolecular layer obtained by the present invention fromthe side, a ratio d/L of a separation distance d of the electricallyconductive macromolecular layer from a substrate, to a length L, is atleast 0 and is 0.02 or less. In this way, it is possible to provideelectrically conductive macromolecules in which delamination from thesubstrate is reduced because the warp of the electrically conductivemacromolecular film is small, and it is flat.

Furthermore, an apparatus, including the polymerizing vessel thatcontains the steam atmosphere has at least a device for providing dryair and steam that is generated by a heat exchanger to the polymerizingvessel. Furthermore, it is desirable that the temperature of the steamgenerated by the heat exchanger is higher than the temperature of thedry air. This is so as to reduce variations in the steam concentrationin the polymerizing vessel. In this case, if the temperature of thesteam that is generated by the heat exchanger is higher than thetemperature of the dry air, then the steam, which has the higher thermalcapacity, contacts the polymerized body, and thus the temperature of thepolymerized body can be increased rapidly.

Furthermore, the present invention provides electronic components, inparticular solid state electrolytic capacitors employing electricallyconductive macromolecules in which an electrically conductivemacromolecular film that is flat is obtained by any method describedabove. Furthermore, the present invention provides electroniccomponents, in particular solid state electrolytic capacitors employingan electrically conductive macromolecular film, wherein the density ofthe surface and the rear of the electrically conductive macromolecularfilm is substantially the same. Moreover, the present invention providesa method for manufacturing solid state electrolytic capacitors thatincludes a step of reacting a monomer and an oxidizing agent at 60° C.or less (with no restriction on steam, this may be in a dry atmosphere)and a step of polymerizing in a polymerizing vessel in a steamatmosphere of at least 85° C. in order that dosing of the electricallyconductive macromolecules into the anodic conductor of the solid stateelectrolytic capacitor, which is a porous body containing numerous finepores, is facilitated.

With the present invention, it is possible to provide a low resistanceelectrically conductive macromolecular film whose polymerization speedon the base material side and on the opposite, vapor phase side issubstantially the same, whose density is substantially the same, andwhose adhesion to the base material, in particular glass and ceramics,is favorable, and a method for manufacturing the same, by reacting atleast a monomer and an oxidizing agent to obtain electrically conductivemacromolecules by a chemical polymerization method, the method at leastcomprising reacting the monomer and the oxidizing agent in apolymerizing vessel that contains a steam atmosphere, and to provideelectrically conductive macromolecules wherein delamination from thebase material is small because warp of the electrically conductivemacromolecular film is small, and the film is flat Furthermore, it ispossible to reduce the oxygen concentration (oxygen partial pressure),and to reduce oxygen degradation of the electrically conductivemacromolecules by using steam to provide low resistance electricallyconductive macromolecules. Thus, it is possible to provide solid stateelectrolytic capacitors that suitably combine both low ESR and largecapacity, and a method for manufacturing the same, and also to provideelectronic components in which the electrically conductivemacromolecules are used, and methods for manufacturing those components.

Preferable embodiments of the present invention are described below withreference to the drawings.

As shown in FIG. 3, a capacitor element usually has a structure in whicha dielectric layer 2, a solid state electrolyte 3 and a cathodicconductor 4 are laminated in that order onto an anodic conductor 1. Thecathodic conductor 4 has a double layer structure made from a carbonlayer 5 and a silver-surface electrically conductive resin layer 6. Theanodic conductor 1 is formed from a sintered body, made from a plate,foil or wire of metal that has valve action, and micro-particles of ametal that has valve action, or from a metal foil that has been etched,for example, to increase its surface area. For the valve metal, it ispossible to use at least one selected from the group consisting oftantalum, aluminium, titanium, niobium and zirconium, or alloys ofthese, and is preferably tantalum, aluminium and niobium. The capacitormay also use, for example, tantalum powder and niobium foil or wire.

The dielectric layer 2 is an oxide film of the surface of the anodicconductor 1 that has been electrolytically oxidized, and it is alsoformed within aperture portions of, for example, the sintered body orthe etched foil. The thickness of the oxide layer film can be controlledby the voltage of the electrolytic oxidation.

The solid state electrolyte 3 includes at least an electricallyconductive macromolecular layer. It is preferable that the electricallyconductive macromolecular layer includes at least one polymer selectedfrom, for example, polypyrrole, polythiophene, polyaniline andpoly-3,4-ethylenedioxythiophene, and particularly pyrrole, thiophene and3,4-ethylenedioxythiophene and their derivatives. The electricallyconductive macromolecular layer can be formed by chemical oxidationpolymerization using a monomer such as pyrrole, a dopant such asalkylnaphthalenesulfonic acid and an oxidizing agent such as manganesedioxide, iron (III) sulfate, copper (II) sulfate, sodium persulfate,ammonium persulfate and hydrogen peroxide solution. In addition tochemical oxidation polymerization, the solid state electrolyte may beformed by electrolytic oxidation polymerization, the detail of which isdescribed below.

It should be noted that the solid state electrolyte 3 also may includeoxide electrically conductive bodies such as ruthenium oxide, andorganic semiconductors such as TCNQ complex (7,7,8,8-tetracyanoquinodimethane complex salt).

The cathodic conductor 4 may be provided as a laminated body made from,for example, the carbon layer 5 and the silver-surface electricallyconductive resin layer 6. The carbon layer 5 includes carbon particlesas the electrically conductive particles, and the electrical connectionbetween the silver powder included in the electrically conductive resinlayer 6 and the solid state electrolyte layer 3 is closely maintained bythese carbon particles.

Although omitted from FIG. 3, the capacitor element is a solid stateelectrolytic capacitor in which an anodic lead terminal and a cathodiclead terminal are respectively connected to the anodic conductor 1 andthe cathodic conductor 4, and in which the lead terminals are sealedwithin an outer layer resin, which is, for example, an epoxy resin.

A description of electrolytic oxidation polymerization is given belowwith reference to FIG. 4.

FIG. 4 shows an example of an arrangement of various polymerizingelectrodes used in electrolytic oxidation polymerization. As shown inthese diagrams, electrolytic oxidation polymerization is performed byimmersing a film forming substrate on which the film is to be formed(the anodic conductor 1 that has been conferred with conductivity inadvance), a polymerization anode (anodic electrode) 7 and apolymerization cathode (cathodic electrode) 8 into a polymerizingsolution 9. The anode 7 and the cathode 8 are connected to a powersource 12. Usually, the anode 7 is fixed in the vicinity of the filmforming substrate 1. In this case, as shown in FIG. 4, it is preferablethat the anode 7 and the cathode 8 are arranged such that at least apart of the film forming substrate 1 is between the electrodes 7 and 8.

With the present invention, it is easy to achieve a solid stateelectrolytic capacitor that has both low ESR and large capacity, andalso to realize low losses and low current leakage.

The present invention is described in further detail below using workingexamples.

WORKING EXAMPLE 1

It has been confirmed that the attributes of an electrically conductivemacromolecular film change with changes in steam concentration duringchemical oxidation polymerization on a glass substrate. Across-sectional schematic diagram of this situation is shown in FIG. 1.

A glass substrate 11 was washed and dried, after which electricallyconductive macromolecules 10 were formed.Poly-3,4-ethylenedioxythiophene was formed as the electricallyconductive macromolecules. First, the polymerizing solution wasformulated by mixing 2 g of 3,4-ethylenedioxythiophene, 44 g of anethanol solution containing 40 wt % iron (III) alkylnaphthalenesulfonateand 20 g of water. This polymerizing solution was coated onto the glasssubstrate and dried for 5 min at room temperature, after which it waspolymerized by heating at 150° C. for 20 min in atmospheres, theconditions of which were 70 vol % steam (shown in FIG. 1A) and a dryatmosphere of 0 vol % (shown in FIG. 1B). Continuing, after washing theelectrically conductive, macromolecular film in ethanol, washing it in a0.5% citric acid solution at 85° C. and washing it in a hot water showerat 90° C., the electrically conductive macromolecular film was forciblyseparated from the glass substrate and dried at 105° C. for 10 min.Photographs of this taken with an optical microscope are shown in FIG.2A and FIG. 2B. FIG. 2A shows the case of the 70 vol % steam and FIG. 2Bshows the case of the dry atmosphere, that is to say, the case in whichsteam was 0 vol % (the case in which the humidity was below thedetectible limit, as detected by a humidity sensor manufactured byYokogawa Electric Corporation).

Steam in the polymerizing vessel was obtained by introducing dry air andsteam, which is water that has been vaporized by a heat exchanger, intothe polymerizing vessel as schematically shown in FIG. 9. In this case,when the temperature of the steam that has been generated by the heatexchanger is higher than the temperature of the dry air, the steam,which has the higher thermal capacity, contacts the polymerized body,and thus it is possible to increase rapidly the temperature of the bodythat is polymerized. Moreover, the dry air and the steam may be mixed inadvance and then introduced into the polymerizing vessel, as shown inFIG. 10. This is in order to reduce variability in the concentration ofthe steam in the polymerizing vessel. In this case, when the temperatureof the steam that is generated by the heat exchanger is higher than thatof the dry air, the steam, which has the higher thermal capacity,contacts the polymerized body, and thus it is possible to increaserapidly the temperature of the polymerized body.

As is made clear in FIG. 1 and FIG. 2, by performing polymerization in asteam atmosphere, because the speed of polymerization on the basematerial side of the glass substrate, which is the base material, issubstantially the same as the speed of polymerization on the vapor phaseside on the opposite surface, and the density is also substantially thesame, and because adhesion of the molecules to the glass is favorableand the electrically conductive macromolecular film has little warpingand is flat, it is possible to provide electrically conductivemacromolecules that have little delamination from the base material, andit is possible to apply the electrically conductive macromolecules touse in electronic components.

WORKING EXAMPLE 2

An anodic conductor made of sintered pellets was fabricated by formingmicro-powder made from tantalum metal having valve action whose specificsurface area is 100000 μF·V/g, into dimensions of 0.3 mm ×3.0 mm×3.8 mm,and vacuum sintering in a form provided with tantalum wire leads forconnecting the anode. Next, a tantalum oxide film was formed on thesurface of the anodic conductor as a dielectric layer by synthesis underconditions of applying a voltage of 7.5 V to the anodic conductor whilein a 5 wt % aqueous solution of phosphoric acid at 90° C.

The anodic conductor was washed and dried, after which the solid stateelectrolyte was formed. Here, poly-3,4-ethylenedioxythiophene was formedas the electrically conductive macromolecules. First, chemical oxidationpolymerization was performed in order to impart electrical conductivityto the dielectric layer. The polymerizing solution was formulated bymixing 1.8 g of 3,4-ethylenedioxythiophene, 44 g of an ethanol solutioncontaining 40 wt % iron (III) alkylnaphthalenesulfonate and 30 g ofwater: The anodic conductor was immersed in the polymerizing solutionand polymerized in air at 40° C. for 10 min, after which chemicaloxidation polymerization was performed by repeating the polymerizationoperation six times in a combination of five conditions of steamconcentrations of 70 vol %, 40 vol %, 10 vol %, 5 vol % arid 0 vol %,and four conditions of temperatures of 85° C., 105° C., 155° C. and 205°C. Continuing, the dielectric layer was resynthesised in a 0.1%concentration solution of acetic acid at a resynthesizing voltage of 7.5V, and restored. Moreover, the anodic conductor was washed in pure waterat about 90° C., and dried in air at about 120° C. FIGS. 5A-5Cschematically show top and cross-sectional views of elements created inconditions of 155° C. and moisture ratio of 0 vol % (comparativeexample) and FIGS. 6A-6B schematically shows top and cross-sectionalviews of elements created in conditions of 155° C. and a moisture ratioof 70 vol %. No delamination was observed in the electrically conductivemacromolecular film created in the conditions of 155° C. and steam of 70vol %. In this way, an anodic conductor in which a dielectric layer andan electrically conductive macromolecular film are formed by chemicaloxidation polymerization was obtained as a film fanning substrate forelectrolytic oxidation polymerization.

The arrangement of the electrodes for electrolytic oxidationpolymerization is as shown in FIG. 4. Nickel wire having a wire diameterof 200 μm was fixed in the vicinity of the film forming substrate as theanode, and was immersed with the cathode into the polymerizing solution.The polymerizing solution was formulated by mixing 100 g of 40 wt %aqueous sodium alkylnaphthalenesulfonate solution, 10 g of3,4-ethylenedioxythiophene, 500 g of water and a predetermined amount ofsulfuric acid. Here, the sulfuric acid was added such that the pH was apredetermined value of 7.

The electrolytic oxidation polymerization was performed at an appliedvoltage of 2.5 V. The time for polymerization was adjusted such that thethickness of the electrically conductive macromolecular layer, being thesurface layer on the film forming substrate, was uniformly about 20 μm.

Continuing, the anodic conductor in which the electrically conductivemacromolecular layer was formed was immersed in an aqueous suspensioncontaining carbon micro particles, and was stood in 130° C. air for 30minutes to dry and harden the suspension. In this way, a carbon layerwas formed on the electrically conductive macromolecular layer.Moreover, the anodic conductor was allowed to stand immersed in a silverpaint solution at room temperature for one hour, and was removed andstood in air at 145° C. for one hour to dry and harden the silver paint.In this way, a silver-surface electrically conducting resin layer wasformed.

Furthermore, using silver conductive adhesive, a cathodic lead terminalwas connected to the cathodic conductor, which is made of the carbonlayer and the silver-surface electrically conductive resin layer, andthe tantalum wire that extends from the anodic conductor was welded tothe anodic lead terminal. Finally, the capacitor elements wereexternally covered with an epoxy resin to complete the solid stateelectrolytic capacitor.

For the solid state capacitors obtained in this way, the staticelectricity capacity was measured at a frequency of 120 Hz and 100 kHz,and the ESR was measured at a frequency of 100 kHz. Moreover, a currentrecorded 30 seconds after a voltage of 2.5 V was applied to the solidstate capacitors was taken as the leakage current. The results are shownin FIGS. 7A-7B, and FIGS. 8A-8B. FIGS. 7A-7B respectively show averagevalues of 20 sample points.

As shown in FIGS. 7A-7B and FIGS. 8A-8B, it can be seen that largecapacity, low ESR and low leak current electrolytic capacitors can beobtained by polymerization in a steam atmosphere. Furthermore, it waspossible to reduce the oxygen concentration (oxygen partial pressure)and reduce the oxygen degradation of the electrically conductivemacromolecules to obtain low resistance electrically conductivemacromolecules, and to obtain electrically conductive macromoleculeswhose film delamination is small, so that solid state electrolyticcapacitors that suitably combine both low ESR and large capacity wereobtained.

Furthermore, cross-sections of the capacitor of the present invention,and of the comparative example, were exposed by grinding, after whichthe interface between a first electrically conductive macromolecularlayer (chemical polymerization layer) and a second electricallyconductive macromolecular layer (electrolytic oxidation polymerizationlayer) was exposed by ultrasonic irradiation while in a 1 mol/L aqueoussolution of hypochloric acid. On inspection under a microscope, theratio d/l of a separation distance d, of the cross-section of the firstelectrically conductive macromolecular layer 10 from the surface of theanodic conductor 1, to a length L of the cross-section in the directionof the anodic conductor (FIG. 5C) was substantially 0.02 or less in thepresent working example, and 0.03 or more in the comparative example.

WORKING EXAMPLE 3

An anodic conductor made of sintered pellets was fabricated by formingmicro-powder made from tantalum metal having valve action whose specificsurface area is 100000 μF·V/g, into dimensions of 0.3 mm×3.0 mm×3.8 mm,and vacuum sintering in a form provided with tantalum wire leads forconnecting the anode. Next, a tantalum oxide film was formed on thesurface of the anodic conductor as a dielectric layer by synthesis underconditions of applying a voltage of 7.5 V to the anodic conductor whilein a 5 wt % aqueous solution of phosphoric acid at 90° C.

The anodic conductor was washed and dried, after which the solid stateelectrolyte was formed. Here, poly-3,4-ethylenedioxythiophene moleculeswere formed as the electrically conductive macromolecules. First,chemical oxidation polymerization was performed in order to impartelectrical conductivity to the dielectric layer. The polymerizingsolution was formulated by mixing 1.8 g of 3,4-ethylenedioxythiophene,44 g of an ethanol solution containing 40 wt % iron (III)alkylnaphthalenesulfonate and 30 g of water. The solid state capacitors(sample 1 and sample 2) were fabricated by immersing the anodicconductors in this polymerizing solution and polymerizing in air at 60°C. for 10 min, after which they were polymerized at a temperature of155° C. in two conditions: steam at a concentration of 70 vol %(fabrication condition of sample 1) or 0 vol % (fabrication condition ofsample 2). Continuing, the anodic conductor was resynthesized in anapproximately 0.1% concentration acetic acid solution at aresynthesizing voltage of 6 V, wherein chemical oxidation polymerizationwas performed by regenerating the dielectric layer 20 times.

Continuing, the anodic conductor on which the electrically conductivemacromolecular layer was formed was immersed in an aqueous suspensioncontaining carbon microparticles, and was stood in 130° C. air for 30minutes to dry and harden the suspension. In this way, a carbon layerwas formed on the electrically conductive macromolecular layer.Moreover, the anodic conductor was allowed to stand immersed in a silverpaint solution at room temperature for one hour, and was removed andstood in air at 145° C. for one hour to dry and harden the silver paint.In this way, a silver-surface electrically conducting resin layer wasformed.

Furthermore, using silver electrically conductive adhesive, a cathodiclead terminal was connected to the cathodic conductor, which is made ofthe carbon layer and the silver-surface electrically conductive resinlayer, and the tantalum wire that extends from the anodic conductor waswelded to the cathodic lead terminal. Finally, the capacitor elementswere covered externally with an epoxy resin to complete the solid stateelectrolytic capacitors.

For the solid state capacitors obtained in this way, the staticelectricity capacity at a frequency of 120 Hz and 100 kHz, and the ESRat a frequency of 100 kHz were measured. Moreover, a current recorded 30seconds after a voltage of 2.5 V was applied to the solid statecapacitors was taken as the leakage current. The result is shown inTable 1. Table 1 shows the minimum and maximum values of the 20 samplepoints on the upper rows, and the average values on the lower rows,respectively.

TABLE 1 120 Hz - 100 kHz - 100 kHz - leakage capacity (μF) capacity (μF)ESR (mΩ) current (μA) Sample 1 255-290 226-254 22-31 190-420 278 239 28240 Sample 2 240-282 193-231 35-47 330-690 261 212 40 450 Sample 3248-287 219-244 25-36 230-480 264 230 30 300

As shown in Table 1, it can be seen that large capacity, low ESR and lowleak current electrolytic capacitors can be obtained by polymerizationin a steam atmosphere. Furthermore, it is possible to reduce the oxygenconcentration (oxygen partial pressure) and reduce the oxygendegradation of the electrically conductive macromolecules to obtain lowresistance electrically conductive macromolecules, and to obtainelectrically conductive macromolecules whose film delamination is small,so that solid state electrolytic capacitors that suitably combine bothlow ESR and large capacity are obtained. Results similar to those ofWorking Example 2 could be obtained, and it can be seen thatpolymerization within steam can be suitably used over a wide range ofapplications.

Further preferable aspects of the present invention are described below.

-   1. An electronic part including an electrically conductive    macromolecular film obtained by any method described in the present    specification, wherein the electronic part uses an electrically    conductive film that is flat.-   2. The electronic part according to the first aspect, wherein the    density of the surface and the rear of the electrically conductive    macromolecular film is substantially the same.-   3. The electronic part according to the first or the second aspect,    wherein the electronic part is a solid state electrolytic capacitor    that includes an anodic conductor made from valve metal, a    dielectric layer formed on the surface of the anodic conductor, and    a solid state electrolyte that is formed on the surface of the    dielectric layer and that includes at least an electrically    conductive macromolecular layer.-   4. A method for manufacturing a solid state electrolytic capacitor    that includes an anodic conductor made from valve metal, a    dielectric layer formed on the surface of the anodic conductor, and    a solid state electrolyte that is formed on the surface of the    dielectric layer and that includes at least an electrically    conductive macromolecular layer, wherein the anodic conductor is    manufactured by a step of reacting a monomer and an oxidizing agent    at 60° C. or less, and a step of polymerizing in a polymerizing    vessel in a steam atmosphere at a temperature of at least 85° C.

1. A method for manufacturing electrically conductive macromolecules bya chemical polymerization method, the method comprising: apolymerization process of reacting a monomer and an oxidizing agent; anda chemical oxidation polymerization process performed in a polymerizingvessel that contains steam atmosphere, after the polymerization process.2. The method for manufacturing electrically conductive macromoleculesaccording to claim 1, wherein the polymerization process is performed at60° C. or lower.
 3. The method for manufacturing electrically conductivemacromolecules according to claim 1, wherein the temperature of thesteam atmosphere is at least 105° C.
 4. The method for manufacturingelectrically conductive macromolecules according to claim 1, whereinsteam concentration in the stream atmosphere is at least 10 vol %. 5.The method for manufacturing electrically conductive macromoleculesaccording to claim 1, wherein concentration of oxygen in the steamatmosphere is lower than 21 vol %.
 6. The method for manufacturingelectrically conductive macromolecules according to claim 1, wherein themonomer is at least one selected from pyrrole, thiophene,3,4-ethylenedioxythiophene, aniline and derivatives of these.
 7. Themethod for manufacturing electrically conductive macromoleculesaccording to claim 1, wherein the oxidizing agent is at least oneselected from manganese oxide, iron (III) salts, copper (II) salts,hydrogen peroxide and persulfate salts.
 8. The method for manufacturingelectrically conductive macromolecules according to claim 1, wherein themonomer and the oxidizing agent are at least dissolved in a watersoluble solvent or water.
 9. The method for manufacturing electricallyconductive macromolecules according to claim 1, wherein when observing alayer of the electrically conductive macromolecules from the side, aratio d/L of a separation distance d of the electrically conductivemacromolecular layer from a substrate, to a length L, is 0.02 or less.10. A solid state electrolytic capacitor comprising: an anodic conductormade from valve metal; a dielectric layer formed on a surface of theanodic conductor; and a solid state electrolyte that is formed on asurface of the dielectric layer and that includes an electricallyconductive macromolecular layer; wherein the electrically conductivemacromolecular layer is formed by a chemical polymerization method, themethod comprising: a polymerization process of reacting a monomer and anoxidizing agent; and a chemical oxidation polymerization processperformed in a polymerizing vessel that contains a steam atmosphere,after the polymerization process.
 11. The solid state electrolyticcapacitor according to claim 10, wherein the anodic conductor provides aporous body containing numerous fine pores.